Over time, the detergent industry has developed textile detergents having continuously improved detergency. Although this is positive and desirable for hygienic reasons, the adverse effect, particularly after a number of wash cycles, cannot be overlooked; colored textiles or textiles imprinted with color undergo fading to a greater or lesser extent.
Color leaching is even more undesirable if the dyes released into the wash liquor are transferred onto other textiles.
Attempts have therefore been made in the past to solve the problem in various ways, such as, for example, by treating the textiles with "dye scavengers" during the washing operation.
The use of color fixatives, which are intended to improve adhesion of the dyes to the fiber, and which are added to the detergent or to the rinse, has also been proposed on several occasions (EP-A-0 704 523, EP-A-0 341 205, EP-A-0 462 806, WO 94/11482, EP-A-0 811 679).
Some progress has been made, but primarily only as a result of high fixative concentrations of about 5-8%, by weight. There is thus a continued need for laundry fabric softeners which have reduced concentrations of fixatives coupled with a high color-retaining action.